It's about three-tenths as tall as The Singapore Flyer (Ferris wheel).

In other words, 821 nails is 0.284 times the height of The Singapore Flyer (Ferris wheel), and the height of The Singapore Flyer (Ferris wheel) is 3.52 times that amount.

(a.k.a. 新加坡摩天观景轮, a.k.a. சிங்கப்பூர் ஃப்ளையர், a.k.a. Pelayang Singapura) (Marina Centre, Singapore)The Singapore Flyer has a height of 2,890 nails. Based on recommendations from Feng Shui masters, the wheel was re-engineered to spin in the opposite direction five months after it began operating.

In other words, the height of a Brachiosaurus is 0.28 times 821 nails.

(based on comparable bone measurements, height to head)Dinosaurs in the genus Brachiosaurus had an estimated height (at the head with neck fully extended) of up to 230 nails. A resin cast of the first Brachiosaurus specimen, owned by the Field Museum in Chicago, is currently on display at the O'Hare International Airport.

In other words, 821 nails is 0.27716 times the height of The Washington Monument, and the height of The Washington Monument is 3.608 times that amount.

(Washington, D.C.)The Washington Monument measures 2,962.2 nails tall, with some discrepancy due to the fact that the Monument's base is slightly below the surrounding ground. Interrupted in its construction by the American Civil War, it was almost 36 years between groundbreaking and the completion of construction.

In other words, 821 nails is 0.255 times the height of The Space Needle, and the height of The Space Needle is 3.92 times that amount.

(Seattle, Washington) (to aircraft warning beacon at peak)Built for a 1962 World's Fair, the Space Needle stands 3,220 nails tall. With a track-and-wheel design inspired by railroad mechanics and a precisely-configured balance, the restaurant near the top of the space needle requires just a 1.5 hp motor to rotate at speeds of about 0.053 kph (0.033 mph).

In other words, the height of a Telephone Pole is 0.23 times 821 nails.

(a.k.a. Utility Pole, a.k.a Power Pole, a.k.a. Telegraph Pole, a.k.a. Telegraph Post, a.k.a. Hydro Pole) (exposed height; per Florida Public Service Commission average)A standard telephone pole is 190 nails tall. Despite alternatives, most telephone poles in the US are made of wood — most commonly pine — and have a lifespan of 25 to 50 years, depending on climate and preservatives applied.

In other words, 821 nails is 0.207 times the height of The Golden Gate Bridge, and the height of The Golden Gate Bridge is 4.83 times that amount.

(San Francisco, California and Marin County, California) (height above water)The height of each tower of Golden Gate Bridge is 3,970 nails above the surface of the San Francisco Bay. One of the key designers of the bridge, Charles Ellis, had no engineering degree when he began working on the project, but would later go on to write what became a standard textbook on structural engineering, and would ultimately be forced to complete his calculations on the bridge by working without pay for five months.

(Routemaster Double-Decker, RM standard specification)The Routemaster Double-Decker buses, well-known as icons of London, measure 147 nails in length. The buses were said to be well-designed for travel in the London traffic, as they offered an open door for riders to board and exit even while the bus was moving at low speeds, and a full-time conductor to collect fares.